The invention relates to a process for mounting a baseplate to a pole comprising reinforced synthetic resin and formed by centrifugal casting within a mold. The baseplate is preferably fashioned of a rustproof material such as zinc coated steel, and is connected with a pipe extension which is oriented perpendicular to the baseplate and which is adapted to be disposed within the base of the pole such that the longitudinal axis of the pipe is substantially aligned with the longitudinal axis of the pole. Such a baseplate serves to fasten and secure the pole to pavement, bridges and other sturdy base supports.
Previous baseplates have been attached to poles with adhesives, which requires an additional fabrication step and thereby complicates production and increases production costs. Therefore, it is an object of the present invention to simplify the fabrication of such a pole prepared by centrifugal casting and the attachment of a baseplate thereto. It is a further object of the present invention to improve the bonding strength of the attachment of the baseplate to the pole. These objects are accomplished according to the present invention by releasable attaching the baseplate to the mold in which the pole is centrifugally cast such that the pipe extension connected thereto is substantially concentrically disposed within the mold and then injecting the synthetic resin within the mold while it is rotating such that the annular space between the mold inner wall and the pipe extension is filled with resin. Thus, the pole is made and the baseplate is fastened thereto in a single operation.
The fabrication process of the present invention obviates the need to finish the base end of the pole associated with previous pole fabrication and baseplate attachment processes. Furthermore, the instant fabrication process requires the additional step only of releasable attaching the baseplate to the mold, which mold may be a mold otherwise conventionally used for centrifugally casting poles comprising reinforced synthetic resin.
The fabrication process of the present invention may be utilized with a variety of centrifugal casting techniques used to form synthetic resin poles, including the techniques disclosed in our copending U.S. patent application Ser. No. 229,409 filed on Jan. 29, 1981, now U.S. Pat. No. 4,383,965, entitled "Centrifugal Process For The Production of A Pipe-shaped Body And A Pipe-shaped Body Produced According To The Centrifugal Process", the disclosure of which is hereby incorporated herein by reference.
Because poles manufactured by centrifugal casting are usually conical with the baseplate being fastened to the end of the pole with the greatest diameter, i.e., the base end, the synthetic resin sprayed into the mold runs along the inner wall of the rotating mold toward the base end where it reaches the annular gap between the mold inner wall and the pipe extension. The synthetic resin fills the gap and thereby causes the pipe extension, and consequently also the baseplate, to be firmly attached to the pole.
The baseplate may be fastened to the mold in various ways. It was found to be particularly advantageous to fasten the baseplate to a raceway of the mold located adjacent to the base end thereof. Since the baseplate is already provided with boreholes for anchoring screws, bolts or the like, it is contemplated that corresponding boreholes are provided in the raceway so that the baseplate can be secured by bolts or the like tightly to the raceway in a plane substantially perpendicular to the longitudinal axis of the mold.
The present invention also extends to a baseplate for the execution of the above-described process. Specifically, the baseplate is provided with an aperture communicating with the pipe extension interior. Such a construction allows the synthetic resin to be sprayed into the mold at the base end of the mold, through the aperture and the pipe extension, if desired.
Other features which are considered characteristic of the invention are set forth in the appended claims.
Although the invention is illustrated and described in relationship to specific embodiments, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.